Air spring actuated slider for semi-trailer

ABSTRACT

An air spring actuated slider pin release system for a semi-trailer slider includes an actuator shaft oriented to extend in generally parallel relationship to at least one of a pair of parallel main members, being connected to the slider for axial rotation, and having a transverse lever arm secured to each end of the shaft for common rotation. Each lever arm has an end connected to a retractable, biased lock pin via a link so that rotation of the shaft and the lever arms causes retraction of the associated lock pin relative to the main member. The actuator shaft has a normally projecting air spring bracket. An air spring is disposed between one of the main members and the air spring bracket so that inflation of the air spring acts on the air spring bracket, axially rotating the shaft and the lever arms for retracting the lock pins.

RELATED APPLICATION

This application is a Continuation of, and claims 35 USC 120 priorityfrom, U.S. patent application Ser. No. 15/195,709 filed Jun. 28, 2016,which is incorporated by reference.

BACKGROUND

This invention relates generally to pin retractors for semi-trailersalso referred to as semi-trailer tandems, and more specifically to arelatively simple mechanism for retracting multiple pins of a tandemusing an air spring.

Conventional semi-trailers of the type hauled over the road by trucksconnect to the truck at a hitch or fifth wheel, and include a tandem,referring to a pair or multiple pairs of parallel axles. In manytrailers, the tandem is slidable forward and backward relative to thetrailer for adjusting the load on the rear axle or axles. The ability tomove the tandem relative to the cargo containing portion of thesemi-trailer is desirable for a number of reasons. When a tractor andsemi-trailer must maneuver around city streets, relatively tight cornersare common. By moving the tandem forward, it is easier to negotiatetight corners. In contrast, when traveling on highways, moving thetandem to the rear of the cargo container puts a larger percentage ofthe load on the axles of the tractor, providing a better ride.

The tandem is secured in position relative to the trailer using at leastone and preferably four retractable lock pins. The pins are typicallyprovided in pairs, members of each pair engaging opposing points of leftand right rails on the trailers. Being biased, usually by a coiledspring or the like, the pins extend laterally or transversely to thedirection of travel of the trailer and engage openings in the dependingrails having a linear array of the openings for accommodating varioustrailer/slider positions. Using the pins, the slider is held in positionrelative to the trailer.

When the pins are retracted, they are also disengaged from the openingsor apertures in the trailer rails, and allow the trailer to be slidforward or backwards relative to the slider. It is conventional toprovide a front and/or rear stop for preventing excessive travel of thetrailer relative to the slider to the extent that the slider disengagesfrom the trailer.

While manual mechanisms are well known for retracting the lock pins,they are subject to jamming, and are inherently more labor intensive forthe operator. Pneumatically powered pin retraction mechanisms have beendeveloped, but are considered costlier and mechanically more complicatedthan the manual systems. In the latter systems, a shaft rotates underthe power of a pneumatic inflatable member, which retracts the pins. Airis supplied to the pneumatic pin retraction system from the existingvehicle trailer braking system. Conventional pneumatic pin retractionsystems are considered more prone to breakdown and require relativelymore maintenance than manual systems.

Thus, there is a need for an improved automatic slider locking pinsystem that addresses the above-identified drawbacks.

SUMMARY

The above-listed need is met or exceeded by the present air springactuated slider for a semi-trailer, which features a single pneumaticactuator, constructed and arranged so that inflation of the actuatorcauses rotation of a main actuator shaft that extends parallel to theaxis of the trailer. Rotation of the shaft causes retraction of the lockpins, overcoming an outward biasing force. Thus, a single inflatablemember controls the retraction of all four lock pins. Preferably, theinflatable member, an air spring, is disposed directly between one ofthe slider frame members and an air spring bracket integral with theactuator shaft. Thus, inflation or deflation of the air spring causesrespective rotation of the actuator shaft through the air bracket.

In addition, the lock pins are connected to the shaft via linkages thatare secured to levers of the shaft using a tab and slot connectionsystem without the use of tools. The present slider pin retractionmechanism is relatively easily assembled, so that all the components arein place prior to installation of the air spring, which exerts tensionon the system. Another feature of the present system is that theactuator shaft is located in an offset position on the slider, beingcloser to one of the main frame members than to the other.

More specifically, the present invention provides an air spring actuatedslider pin release system for a semi-trailer slider having a pair ofmain members extending along a longitudinal axis of the slider, and atleast one cross member separating the main members in spaced, parallelrelationship to each other. Included in the air spring actuated sliderpin release system is an actuator shaft oriented to extend in generallyparallel relationship to at least one of the main members, beingconnected to the slider for axial rotation, and having a transverselever arm secured to each end of the shaft for common rotation. Eachlever arm has an end connected to a retractable, biased lock pin via alink so that rotation of the shaft and the lever arms causes retractionof the associated lock pin relative to the main member. The actuatorshaft has a normally projecting air spring bracket. An air spring isdisposed between one of the main members and the air spring bracket sothat inflation of the air spring acts on the air spring bracket, axiallyrotating the shaft and the lever arms for retracting the lock pins.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top perspective view of the present slider;

FIG. 2 is an enlarged fragmentary view of the slider of FIG. 1;

FIG. 3 is a fragmentary overhead perspective view of the present slider;

FIG. 4 is an enlarged fragmentary side view of the present lever arm andlock pin assembly;

FIG. 5 is a fragmentary top perspective view of the present air springdisposed in the slider and connected to the pin retraction mechanism;and

FIG. 6 is a fragmentary bottom perspective view of the present slidershowing the actuation button.

DETAILED DESCRIPTION

Referring now to FIGS. 1 and 2, a semi-trailer slider is generallydesignated 10 and includes a pair of spaced, parallel main members 12extending along a longitudinal axis of the slider, rigidly secured toeach other by a pair of transverse cross members 14 by welding or otherfastening technique well known in the art. Once joined, the members 12and the cross members 14 form a slider frame 16. As is known in the art,the slider frame 16 has a front end 18 facing a front of the trailer andthe tractor (not shown), and an opposite rear end 20. Also, as iscommon, the slider 10 provides for at least one and preferably a pair ofsets of trailer wheel mounting points 22, each having associated brakes24, axle spindles 26, connecting arms 28, suspension trailing arms 30,pneumatic springs 32 and other running gear components well known tothose skilled in the art.

As is common with such sliders 10, at least one and preferably fourbiased retractable lock pins 34 extend laterally beyond outer surfaces36 of the associated main members 12. Thus, in the preferred slider 10,two lock pins 34 extend from each surface 36. The present slider pinrelease system includes an actuator shaft 38 extending between, andsupported by the cross members 14. Each of the cross members 14 has afront surface 40 and a rear surface 42. The actuator shaft 38 isrotatably disposed relative to the cross members 14, being located in asocket 44 in the rear cross member 14 b and rotatably engaged in a shaftopening 46 in the front cross member 14 a. The actuator shaft 38 hasfirst and second ends, 48, 50. A transverse lever arm 52 is securelymounted, as by welding or the like adjacent each end 48, 50 of theactuator shaft 38 for common rotation upon axial rotation of the shaftrelative to the slider 10.

In the preferred embodiment, the actuator shaft 38 is disposed to becloser to one of the main members 12 than to the other member. As such,the shaft 38 is laterally offset when viewed from the front or rear ends18, 20 of the slider frame 16.

Referring now to FIGS. 1, 3 and 4, as will be described in greaterdetail below, the single actuator shaft 38 operates all of the lock pins34 on the slider 10. Free ends 54 of the lever arm 52 are connected tothe corresponding lock pins 34 via elongate linkage elements 56, such asmetal straps. More specifically, each ever arm free end 54 is associatedwith a particular lock pin 34. For reaching the lock pins 34 locatedrelatively close to the actuator shaft 38 as well as relatively fartheraway, the linkage elements 56 are provided in short lengths 56 a andlonger lengths 56 b (FIG. 4).

The lever arm free ends 54 are each preferably provided in a hook or tabconfiguration (Best seen in FIGS. 2 and 3) which slidably engagescorresponding slots 58 in the linkage elements 56. Thus, the linkageelements 56 are assembled on the lever arms 52 without the use of tools.

As seen in FIG. 3, also as known in the art, the slider 10 is preferablyprovided with a plurality of multi-apertured air line guides 60 forsupporting the vehicle air lines 61 (FIG. 5) transmitting pressurizedair from one end of the slider to the other. The air line guides 60 arepreferably connected to the actuator shaft 38. The slider frame 16 isalso preferably provided with a compressed air storage tank 62 in fluidcommunication with the slider and the vehicle pneumatic power systems asknown in the art.

Referring now to FIG. 4, further details are shown of the connectionbetween the lock pins 34 and the lever arms 52. Each lock pin 34includes an end 64 projecting from the main member surface 36 and isheld in place in part by a radial flange 66. An elongate pin shaft 68extends from the end 64, passes through the main member 12, and has anopposite, connection end 70 with a generally “T”-shaped stud or lug 72projecting generally perpendicularly from the shaft 68. The stud 72releasably engages a pin end 74 of the linkage element, here linkageelement 56 a. Although the shape may vary to accommodate theapplication, the pin end 74 has an aperture 76 constructed and arrangedfor positively and releasably engaging the stud 72 without the use oftools. Also, a pin return spring 78 surrounds the pin shaft 68 and isdisposed in an interior space 80 of the member 12. By engaging anintegral collar 82 on the pin shaft 68, the spring 78 urges the lock pinend 64 outwardly relative to the member 12. While only one of the lockpins 34 is shown in detail, it will be understood that all four lockpins in the slider 10 are similarly constructed and arranged.

As the actuator shaft 38 rotates clockwise, it will be seen that thelever arm 52 pulls on the respective linkage elements 56 a, 56 b,causing the elongate pin shafts 68 to move inboard away from the outermember surfaces 36 and thus overcoming the biasing force exerted by thespring 78. Upon sufficient rotation of the actuator shaft 38, the lockpin 34 will be fully retracted. It should be noted in FIG. 4 that thefree ends 54 of the lever arm 54 each extend in opposite directions,reflecting the direction from which the respective linkage element 56 a,56 b extends. Also, the lever arm 54 rotates in a plane that is parallelto that of the cross member 14 and transverse to the axis of theactuator shaft 38.

Referring now to FIG. 5, a view on the opposite side of the main member12 depicts an interior 84 of the slider frame 16. An important featureof the present slider pin retraction system, generally designated 86, isthe provision of an inflatable air spring 88 disposed between one of themain members 12 and an air spring bracket 90 fixed to the actuator shaft38 for common rotation. The air spring 88 is in fluid communication withthe vehicle pressurized air system and the storage tank 62. In thepreferred embodiment, the air spring bracket 90 projects perpendicularlyor normally to the axis of the actuator shaft 38, and features agenerally flat base 92 generally parallel to and opposing the adjacentmember 12. The air spring 88 is preferably an inflatable bladderdisposed between the main member 12 and the air spring bracket 90 sothat inflation of the air spring acts directly on both the main member12 and the air spring bracket, and thus directly upon the actuator shaft38, axially rotating the air spring bracket, the actuator shaft and thelever arms 52 about the axis which is parallel to the main member and tothe direction of travel of the slider 10 to simultaneously retract allof the lock pins 34 on the slider.

In the preferred embodiment, as is the case with the actuator shaft 38,the air spring 88 and the air spring bracket 90 are located closer toone of the main members 12 than to the other. More specifically,although other locations are contemplated on the slider frame 16, it ispreferred that the air spring 88 and the air spring bracket 90 arelocated in a corner defined by adjacent ends of the corresponding mainmember 12 and the closest cross member 14. Also, the air spring 88 andthe air spring bracket 90 are located on one side of the associatedcross member 14, and the closest lever arm 52 is located on the oppositeside of the cross member.

Another feature of the air spring bracket 90 is a stop member 94, morespecifically a stop bar secured to an opposite surface of the bracketfrom the air spring 88, and projecting laterally from the bracket. Thestop member 94 passes through an opening 96 in the cross member 14 sothat as the air spring 88 is deflated (pins extending), the bracket 90will tilt backwards, rotating the actuator shaft 38, until the stopmember contacts an edge 98 of the opening. At the point of contact, thedeflating movement of the air spring bracket 90, and the rotation of theactuator shaft 38 will stop. Thus, the air spring 88 is prevented fromcollapsing excessively. At this point, the four lock pins 34 are fullyextended, preventing sliding of the slider 10 relative to the trailer.

Once the operator is ready to lock the slider 10 in its new positionrelative to the trailer, the air spring 88 is depressurized. A bracketreturn spring 100 connected between the air spring bracket 90 and themember 12 reverses the action caused by the air spring 88 and pulls thebracket back to the default (extended pin) position, releasing thepulling force on the linkage elements 56 a, 56 b and allowing the pinreturn springs 78 to force the pin ends 64 back outwards relative to theouter member surfaces 36.

Referring now to FIG. 6, the operator controls the retraction of thelock pins 34 by the inflation/deflation of the air spring 88 through aconventional manually activated air valve 102. As is well known in theart, the air valve 102 is in fluid communication with the air spring 88and with the vehicle pressurized air system. Although a variety ofmanually activated valves are contemplated, the present air valve 102 isof the pull/push button type. To activate the air spring 88, and retractthe lock pins 34, the operator pulls on the air valve control button104. Once the vehicle operator has completed the movement of the slider10 relative to the trailer, and desires that the slider and the trailerare locked together for travel, the control button 104 is pushed in,causing deflation of the air spring 88. As the spring 88 deflates,counter rotation of the actuator shaft 38 is assisted by the biasingaction of the spring 100. Also, the biasing action of the pin returnsprings 78 pushes the lock pins 34 to the laterally outwardly projectinglocking positions shown in FIG. 1.

Referring now to FIGS. 1 and 5, in the preferred embodiment, at leastone mounting bolt 106 is used to secure the stop member 94 to the airspring bracket 90. In addition, the same bolt 106 or bolts secure(s) theair spring 88 in position on the bracket 90. It will be seen that theair spring 88 and the air spring bracket 90 are disposed within a spacedefined by upper and lower edges 108, 110 of the main members 12 andupper and lower edges 112, 114 of the at least one cross member 14.Another feature of the present slider 10 is that the air spring 88 andthe air spring bracket 90 are connected to the associated main member 12at a suspension hanger bracket 116 (FIG. 6).

During installation of the slider pin retraction system 86, the actuatorshaft 38 and the air spring bracket 90 are installed in the slider frame16. Next, the lever arms 52 are then secured to the actuator shaft 38and the linkage elements 56 a, 56 b are connected between the lever armsand the lugs 72 on the pin shafts 68. The hook-like tab configuration ofthe free ends 54 of the lever arms 52 are sufficiently long so that thelinkage elements 56 a, 56 b are retained on the lever arm through thefull range of rotation of the actuator shaft 38. Once all of thelinkages 56 a, 56 b for all of the lock pins 34 are installed, the airspring bracket 90 is rotated sufficiently relative to the associatedmain member 12 so that sufficient clearance is created for installationof the air spring 88 and the stop member 94.

While a particular embodiment of the present air spring actuated sliderfor semi-trailer has been described herein, it will be appreciated bythose skilled in the art that changes and modifications may be madethereto without departing from the invention in its broader aspects andas set forth in the following claims.

The invention claimed is:
 1. An air spring actuated slider pin releasesystem for a semi-trailer slider having a pair of main members extendingalong a longitudinal axis of the slider, and at least one cross memberseparating the main members in spaced, parallel relationship to eachother, comprising: an actuator shaft oriented to extend in a generallyparallel relationship to at least one of the main members, beingconnected to said slider for axial rotation, and having a transverselever arm secured to each end of said shaft for common rotation; eachsaid lever arm having an end connected to a retractable, biased lock pinso that rotation of said shaft and said lever arms causes retraction ofsaid associated lock pin relative to the main member; said actuatorshaft having a normally projecting air spring bracket; and an air springdisposed in operational relationship to said air spring bracket so thatinflation of said air spring directly acts on said air spring bracket,moving said bracket transversely to said main members and axiallyrotating said shaft and said lever arms for retracting said lock pins.2. The slider pin release system of claim 1, wherein said air springacts directly on said actuator shaft via said air spring bracket.
 3. Theslider pin release system of claim 1, wherein said air spring is aninflatable bladder disposed to exert inflation pressure between thecorresponding main member and said air spring bracket.
 4. The slider pinrelease system of claim 1, further including a return spring connectedto said air spring bracket and the corresponding main member forrotating said shaft and said levers in an opposite direction from thatcaused by said air spring, for causing extension of said lock pins. 5.The slider pin release system of claim 1, wherein said air spring andsaid air spring bracket are located closer to one of the main membersthan the other.
 6. The slider pin release system of claim 5, whereinsaid air spring and said air spring bracket are located in a cornerdefined by the at least one cross member and one of the main members. 7.The slider pin release system of claim 5, wherein said actuator shaft islocated closer to one of the main members than the other.
 8. The sliderpin release system of claim 1, wherein inflation of said air springcauses retraction of four of said lock pins on said slider.
 9. Theslider pin release system of claim 1, further including anoperator-actuated valve associated with said frame and connected to saidair spring for causing selective inflation of said air spring.
 10. Theslider pin release system of claim 1, in which each said lever arm isconnected to a short and a long linkage for controlling movement of saidlock pins.
 11. The slider pin release system of claim 10, in which eachsaid lever arm has a tab constructed and arranged for engaging a slot onsaid associated linkage, which in turn engages a stud associated with acorresponding one of said link pins.
 12. The slider pin release systemof claim 11, wherein said tabs and slots are constructed and arranged sothat said tabs are engaged in said slots without the use of tools. 13.The slider pin release system of claim 11, wherein said stud isgenerally T-shaped.
 14. The slider pin release system of claim 10, inwhich said short and long linkages are used to connect said lever armsare connected to slider pins associated with each of said opposite mainmembers for achieving simultaneous retraction of said pins.
 15. Theslider pin release system of claim 1, further including a stopassociated with said air spring bracket for engaging a corresponding oneof the cross members for limiting movement of said shaft upon deflationof said air spring.
 16. The slider pin release system of claim 15,further including a mounting bolt used to secure said stop, saidmounting bolt also secures said air spring to said air spring bracket.17. The slider pin release system of claim 1, wherein said air springand said air spring bracket are disposed within a space defined by upperand lower edges of the main members and the at least one cross member.